Rheological investigation of neonatal double-lumen cannula with and without deformable erythrocytes

The double-lumen cannula (DLC) is the most critical component of extracorporeal membrane oxygenation (ECMO) because of its narrow cross-section, thereby developing the highest shear stress in the entire ECMO circuit. To measure blood damage in a DLC, the Eulerian approach is generally used without contemplating exposure time or history of blood exposure to shear stresses. Alternatively, Lagrangian approach has also been recently employed for a Newtonian blood flow through a DLC, thereby leaving a research gap on the impact of variable shear rate in case of non-Newtonian blood flow. In the present study, the hemodynamic performance of DLC is investigated using different non-Newtonian models by applying Lagrangian approach. Moreover, the motion of RBC was tracked inside the cannula to predict its behavior during the motion. The results showed that the return lumen had higher pressure, velocity, and shear stress values than other parts of the DLC. In addition, recirculation was observed due to the mixing of blood coming from different inlets and found increase with increasing flow rate of blood. Moreover, it was found that the blood damage increased with increasing flow rate. There was more blood damage in the Newtonian model than in the other non-Newtonian models at higher flow rates. However, the Carreau model showed more blood damage at lower flow rates than the other models. The Cross model showed DLC’s higher efficacy in delivering oxygenated blood to the tricuspid outlet because it showed the least blood damage among all other models. It was also concluded that the efficacy of the DLC to deliver oxygenated blood to the tricuspid outlet decreases with increasing blood flow rate.